A device for dosing and mixing two components A and B is known from the European patent EP 0 116 879 B1. Each of the two components, which are referred hereinafter also as coating material A and coating material B, is supplied to a flow rate meter by means of a feed pump. Valves are arranged downstream of the two flow rate meters, such valves being pneumatically opened and closed using a control. The rates of flow of the components A and B are measured with the help of the flow meter and corresponding electric measuring signals are sent to the control. If the set volume of the one component is reached, the material flow of this component is interrupted and the flow for the other component is immediately released. The two components A and B are supplied to a 2 chamber mixing block and subsequently definitively mixed in a mixing pipe mounted downstream and sent to a spray gun. However this embodiment has the disadvantage that the flow rate meters cannot be used any more in the case of abrasive materials since they are subject to too high wear.